Re: 2.6.24 says "serial8250: too much work for irq4" a lot.

From: H. Peter Anvin
Date: Thu Feb 07 2008 - 16:12:47 EST


Rob Landley wrote:

Specifically, qemu isn't paravirtualized, it's fully virtualized. The same kernel can run on real hardware just fine. (Sort of the point of the project...)

I can yank the warning for the kernels I build (or set PASS_LIMIT to 9999999), but I'd rather not carry any more patches than I can avoid...


The right thing to do is to add virtual FIFO exhaustion into the Qemu device model. It really isn't a valid emulation of a UART that it has an infinite FIFO behind it that can flood the interrupt handler for an arbitrary number of fetches.

I was going to give a technical description of how to do it here, but then I realized I might as well just write it up as a patch. Stay tuned.

-hpa

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